Bicycle.



' No. 636,038. Patented on. 31, I899.

' J. A. ram-2m.

BICYCLE.

(Application filed Nov. 8, 1888.)

(No Model.)

INITED. STATES PATENT FFIQEB BICYCLE.

SPECIFICATION forming part of Letters Patent No. 636,038, dated October 31, 1899.

Application filed November 8, 1898. Serial No. 695,863. (No model.)

My invention relates to the construction of the frames of bicycles and other velocipedes, and more particularly to those driven by chain gearing.

The object of my invention is to provide a construction of the rear portion of the frame which will permit of the back Wheel being easily and expeditiously removed and replaced. By this means the sprocket-wheel attached to the back wheel can be quickly changed and the gear raised or lowered, as required. I accomplish this object (a) by constructing the rear portion of the frame with a hinged piece forming the lower part of the slot in which the axle of the rear wheel is at tached and (b) by providing a spring-catch by which the sprocket-wheel is retained in place.

Referring to the accompanying drawings, in which myinvention is shown as applied to an ordinary rear-driving bicycle, Figure 1 is a side View of the back portion of the machine, showing the hinged portion of the frame. Fig. 2 is an end View of the clamp and thumbscrew for securing the hinged portion of the frame; and Fig. 3, a section through line a, b, Fig. 1, showing the pivot-bolt of the hinged portion of the frame.

Similar letters of reference indicate corresponding parts throughout the drawings.

A A are the arms of the fork of the rear portion of the framework, formed in the ordinary way of steel tubing, for the reception of the back wheel.

My invention is described with reference to one side only, it being understood that the two are alike.

The arm A, instead of being provided with a slot at its outer side, in the ordinary Way, for

' the reception of the axle of the back wheel,

hinged upon the upper part A by a screwbolt H, passing through the slot A This screw-bolt H is of special construction, as shown in Fig. 4, in order to prevent it moving along in the slot A and at the same time providing a free pivot for the hinged piece A For thispurpose the bolt H is provided,in addition to the head H, with a shoulder 11*, which passes through a hole of corresponding size in the jaw-piece A As the nut H is screwed up this shoulder H bears against the outer side of the upper part A, and the bolt H is thus held rigidly in position in the slot A while allowing the jaw-piece A to move freely thereon. By this means the jawpiece A can be adjusted in the slot A in order to tighten the chain when required. To the rear end of the jaw-piece A is pivoted a clamp B, provided with a thumb-screw B, by means of which the two parts A A are securely held together.

The upper edge of the jaw-piece A is provided with a series of notches 0, adapted to receive one end of the spindle E of the back wheel. The jaw-piece A may be provided with any number of notches 0, according to the desired number of variations in the gear. The notches O serve the purpose of allowing the back wheel to be moved forward or backward, according to the size of sprocket-wheel D employed, in order to give the necessary tension to the chain.

For the purpose of altering the gear the rear sprocket-wheel D is screwed onto the hub G G in the ordinary way; but instead of the usual lock-nut I provide an improved spring-catch for retaining it in position. This spring-catch consists of a small bar F, passing through the flanges G of the hub G of the back wheel and a hole D in the sprocket wheel D and is actuated and held in place by a spring F.

When it is desired to change the gear of the machine, the thumb-screws B upon each side are loosened and the clamp B unfastened. This allows the jaw-piece A to drop, and the chain being slipped over the sprocket the back wheel is easily and expeditiously removed from the frame. The spring catchpiece F is then pulled back and the sprocketwheel D removed. This is now replaced by a fresh sprocket-wheel having a larger or smaller number of teeth, the spring catchpiece F engaging with a hole made therein for the purpose. The back wheel is then replaced in the frame, the ends of the spindle E being placed in the notches in the jawpiece A on each side, so that if the sprocketwheel has a smaller number of teeth than the previous one the spindle is placed in the notches to the rear,while if it possesses a larger number of teeth it is placed in notches to the front, thus giving the necessary tension to the chain. The jaw-piece is then fixed in position by means of the clamps B and thumbscrews B, and the machineis again ready for use.

Having now particularly described and ascertained the nature of my said invention and in what manner the same is to be performed, I declare that what I claim is- 1. In a bicycle or other velocipede, the arm of the fork of the rear portion of the framework made in two parts, a fixed and a movable part, the fixed part provided with an elongated slot and the movable partprovided with a series of recesses on its upper edge each notch adapted to receive the spindle of the back wheel of the vehicle, a screw-bolt by which one end of the movable part of said arm is hinged in the slot of the fixed part of said arm and rendered adjustable in said slot, and means for locking the free end of the movable part to the fixed part.

2. In a bicycle or the like, arm A of the frame having a two-part end, part A rigid with A, and A pivoted thereto, said pivoted part A having notches C with curved bottoms on its upper edge adapted to directly receive a spindle, means for securing the outer end of part A to part A and for releasing the same.

3. In a bicycle or the like, arm A of the frame having a two-part end, part A rigid with A, and A pivoted thereto, by means of an elongated slot in part A and a pivot therein having means to secure it at any desired position in said slot said pivoted part A having notches O with curved bottoms on its upper edge adapted to directly receive a spindle, means for securing the outer end of part A to part A and for releasing the same.

In testimony whereof I have hereunto set my hand in presence of two subscribing witnesses.

JAMES ALEXANDER GREIG. Vitnesses:

EDWIN B. COLTON, CHARLES S. BURGESS. 

